Thermally conductive structure for multidirection flow through packed bed

ABSTRACT

A packed bed for a heat exchanger may comprise a frame and a first fin layer disposed within the frame. A second fin layer may be disposed within the frame. A first perforated sheet may be disposed between the first fin layer and the second fin layer. A sorbent material may be disposed within a volume of at least one of the first fin layer or the second fin layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to and thebenefit of, U.S. Ser. No. 15/347,889 filed on Nov. 10, 2016 and entitled“THERMALLY CONDUCTIVE STRUCTURE FOR MULTI-DIRECTION FLOW THROUGH PACKEDBED.” The above-referenced application is hereby incorporated byreference in its entirety.

FIELD

The present disclosure relates to heat exchangers and, morespecifically, to a packed bed for a heat exchanger assembly.

BACKGROUND

Sorbent heat exchangers may be employed in various applicationsincluding, but not limited to, air purifying systems for mannedspacecraft and submarines. Such systems may remove carbon dioxide (CO₂)from recirculated air so that the air can be re-used for onboardpersonnel. Systems for removing carbon dioxide from the air include mayuse an open cell foam filled with a CO₂ adsorbent material. Size,weight, and manufacturing complexity and cost may be factors consideredin the design of sorbent heat exchanger systems.

SUMMARY

A packed bed for a heat exchanger and carbon dioxide removal system isdescribed herein, in accordance with various embodiments. A packed bedfor a heat exchanger may comprise a frame and a first fin layer disposedwithin the frame. A second fin layer may be disposed within the frame. Afirst perforated sheet may be disposed between the first fin layer andthe second fin layer. A sorbent material may be disposed within a volumedefined by at least one of the first fin layer or the second fin layer.

In various embodiments, the first fin layer may be thermally coupled tothe second fin layer. The packed bed may further comprise a third finlayer disposed within the frame. A second perforated sheet may bedisposed between the second fin layer and the third fin layer. The firstfin layer, the second fin layer and the first perforated sheet maycomprise aluminum. The sorbent material may be configured to adsorbcarbon dioxide. The first fin layer may comprise first lanced offsetfins and the second fin layer comprise second lanced offset fins. Thefirst lanced offset fins may be staggered with the second lanced offsetfins. The first perforated sheet may be brazed to the first fin layerand to the second fin layer.

A heat exchanger assembly is also provided. A heat exchanger assemblymay comprise a first packed bed having a first fin layer and a firstsorbent material disposed within the first packed bed. A second packedbed may be in thermal communication with the first packed bed. Thesecond packed bed may have a second fin layer and a second sorbentmaterial disposed within the second packed bed.

In various embodiments, the first packed bed may comprise a perforatedsheet brazed with the first fin layer. The first fin layer may compriselanced offset fins. The first fin layer, the second fin layer and theperforated sheet may comprise aluminum. The first sorbent material andthe second sorbent material may be configured to adsorb and desorbcarbon dioxide. Heat generated exothermically by adsorption of carbondioxide by the first sorbent material may be transferred to the secondpacked bed. The second packed bed may receive heat from the first packedbed. The heat exchanger assembly may be substantially isothermal.

A method of manufacturing a packed bed for a heat exchanger is alsoprovided. The method may comprise the steps of forming a first fin layerconfigured to fit within a frame, forming a second fin layer configuredto fit within the frame, disposing a perforated sheet between the firstfin layer and the second fin layer, brazing the first fin layer,perforated sheet, and second fin layer to form the packed bed, disposingthe packed bed within the frame, and applying a sorbent material withinthe packed bed.

In various embodiments, the first fin layer may comprise first lancedoffset fins and the second fin layer may comprise second lanced offsetfins, may further comprise staggering the first lanced offset fins withthe second lanced offset fins. The method may further comprise sealingthe packed bed within the frame. The frame may define a fill port. Thestep of applying the sorbent material may further include injecting thesorbent material into the frame through the fill port. The method mayfurther comprise stacking a plurality of packed bed with adjacent packedbeds in thermal communication to form the heat exchanger. The sorbentmaterial may be configured to adsorb carbon dioxide.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the figures, wherein like numerals denotelike elements.

FIGS. 1A and 1B illustrate a perspective view and an exploded view of anexemplary packed bed for heat exchanger, in accordance with variousembodiments;

FIG. 2 illustrates a perspective view of a heat exchanger assembly, inaccordance with various embodiments;

FIG. 3 illustrates an exploded view of a packed bed for a heatexchanger, in accordance with various embodiments;

FIG. 4 illustrates a perspective view of a sorbent bed having lancedoffset fins, in accordance with various embodiments;

FIGS. 5A, 5B and 5C illustrate sorbent beds for a heat exchanger, inaccordance with various embodiments; and

FIG. 6 illustrates a method for manufacturing a heat exchanger assembly,in accordance with various embodiments.

DETAILED DESCRIPTION

All ranges and ratio limits disclosed herein may be combined. It is tobe understood that unless specifically stated otherwise, references to“a,” “an,” and/or “the” may include one or more than one and thatreference to an item in the singular may also include the item in theplural.

The detailed description of various embodiments herein makes referenceto the accompanying drawings, which show various embodiments by way ofillustration. While these various embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical, chemical, and mechanical changes may be madewithout departing from the spirit and scope of the disclosure. Thus, thedetailed description herein is presented for purposes of illustrationonly and not of limitation. For example, the steps recited in any of themethod or process descriptions may be executed in any order and are notnecessarily limited to the order presented. Furthermore, any referenceto singular includes plural embodiments, and any reference to more thanone component or step may include a singular embodiment or step. Also,any reference to attached, fixed, connected, or the like may includepermanent, removable, temporary, partial, full, and/or any otherpossible attachment option. Additionally, any reference to withoutcontact (or similar phrases) may also include reduced contact or minimalcontact. Cross hatching lines may be used throughout the figures todenote different parts but not necessarily to denote the same ordifferent materials.

The present disclosure relates to a packed bed for a heat exchanger,which may be used in a system for removing water and carbon dioxide froman airflow. A heat exchanger for a closed, habitable environment mayinclude a plurality of packed beds, each containing a sorbent materialto form a sorbent bed. The packed beds may be configured to facilitateairflow within the packed beds and to adsorb and desorb carbon dioxide(CO₂) from the airflow. Further, the packed beds may be configured totransfer heat between adjacent packed beds. Each alternating packed bedin the heat exchanger may regenerate while the adjacent packed bedadsorbs CO₂. For example, referring to two adjacent packed beds in aheat exchanger, a first packed bed may operate to filter an airflow byadsorbing CO₂, while a second packed bed may regenerate by desorbingCO₂. Because the adsorption process is exothermic and the desorptionprocess is endothermic, a temperature gradient is established betweenthe two beds that allows for energy transfer between the packed beds. Asthe first packed bed generates heat during the adsorption process, theheat is transferred to the second packed bed. The second packed bed isexposed to a vacuum and uses the heat and vacuum to desorb and releaseCO₂. In various embodiments, the closed environment is a spacecraft andthe vacuum is a space vacuum.

With reference to FIGS. 1A and 1B, a packed bed assembly for a heatexchanger is shown, in accordance with various embodiments. Packed bedassembly 10 includes a packed bed 12 disposed within a frame 20. Packedbed 12 may include one or more heat exchange elements 14, such as fins,and a sorbent material 16. The frame 20 may define a volumetric body orchamber 22 into which packed bed 12 may be placed. Frame 20 may defineone or more openings, such as a first port 24, a second port 26, and afill port 28. First port 24 and second port 26 may permit gas to enterthe chamber 22. Packed bed 12 may be disposed within chamber 22 of frame20 between first port 24 and second port 26, such that an airflow Atravels through packed bed 12. A path of airflow A is defined such thatairflow A may enter first port 24, flow through the pathways definedwithin packed bed 12, and exit through second port 26. Airflow A maytravel in various directions through packed bed 12, including in thex-direction, y-direction, and z-directions in relation to the providedxyz axis.

Packed bed 12 may contain a sorbent material 16, which may be configuredto adsorb and desorb CO₂ and/or water. Sorbent material 16 may comprisesolid CO₂ sorbents such as soda lime, zeolites, molecular sieves, solidoxides, alkali metal carbonates, alkali metal hydroxides, amines, and/orcombinations thereof. In various embodiments, frame 20 further defines afill port 28, which may be used during assembly to dispose sorbentmaterial 16 within packed bed 12. For example sorbent material 16 may beinjected into packed bed 12 through fill port 28. Fill port 28 may besubsequently sealed during operation of the heat exchanger.

Referring to FIG. 1B, a packed bed assembly 10 may comprise a packed bed12 disposed within frame 20. Packed bed 12 may include a plurality oflayers configured to facilitate airflow through packed bed 12 and tofacilitate conduction of heat between first surface 44 and secondsurface 46 of packed bed assembly 10. Packed bed 12 may includeinterposed layers of fin layers 30 and perforated sheets 32. Fin layers30 may be configured to provide a high surface area to volume ratio foroptimized airflow and minimal differential pressures within packed bedassembly 10. Perforated sheets 32 may be configured to couple adjacentfin layers 30 and to permit airflow through the perforations to allowairflow to move between fin layers 30. Sorbent material 16 may bedisposed within a volume defined by at least one of fin layers 30.

Fin layers 30 and perforated sheets 32 of packed bed 12 may further bedisposed within an inner frame 34, which may include a screen 36 forcontaining sorbent material 16 within packed bed 12. One or morepartition layers 40, 42 may be disposed over a first surface 44 and asecond surface 46 of frame 20. Partition layers 40, 42 may operate as aseal at first surface 44 and second surface 46. Partition layers 40, 42may be configured to couple to adjacent packed bed assemblies 10 forheat exchange therebetween.

When assembled into frame 20, a packed bed 12 may have a plurality offin layers 30 coupled by a perforated sheet 32 between the fin layers 30in an alternating pattern. A size and shape of fin layers 30 andperforated sheets 32 may be configured to according to the size andshape of frame 20. Fin layers 30 may be cut to size by laser cutting,milling, electrochemical machining (ECM), discharge machining (EDM), orother suitable process. Frame 20, fin layers 30, perforated sheets 32,inner frame 34 and partition layers 40, 42 may comprise aluminum,aluminum alloy, steel, or stainless steel, copper or other materials.

With reference to FIG. 2, a heat exchanger assembly is shown, inaccordance with various embodiments. The packed bed assembly 10 fromFIGS. 1A and 1B may be disposed in a heat exchanger assembly 60. Aplurality of packed bed assemblies 10 a, 10 b may be stacked orpositioned with adjacent packed bed assemblies abutting one another. Aheat exchanger assembly 60 may comprise at least one packed bed, such asfirst packed bed 12 a and/or second packed bed 12 b. Heat exchangerassembly 60 may include various quantities of packed bed assemblies 10a, 10 b and packed beds 12 a, 12 b Heat exchanger assembly 60 isillustrated in FIG. 2, for example, with first packed bed assembly 10 astacked over a second packed bed assembly 10 b, and with a secondsurface 46 a of first packed bed assembly 10 a in contact with a firstsurface 44 b of second packed bed assembly 10 b. Thus, a first packedbed 12 a may be thermally coupled to a second packed bed 12 b. Secondpacked bed assembly 10 b may be in thermal communication with the firstpacked bed assembly 10A such that heat exchanger assembly 60 may operateisothermally. First packed bed 12 a and second packed bed 12 b may bethermally coupled by direct physical contact or indirect physicalcontact.

In various embodiments, the first sorbent material 16 a disposed withinfirst packed bed 12 a and the second sorbent material 16 b disposedwithin second packed bed 12 b may be configured to adsorb and desorbCO₂. During operation of heat exchanger assembly 60, one of packed beds12 a, 12 b may be adsorbing CO₂ and water, while another of packed beds12 a, 12 b may be desorbing CO₂ and water. For ease of discussion, heatexchanger assembly 60 will be discussed in terms of first packed bed 12a adsorbing CO₂ (filtering) and second packed bed 12 b desorbing CO₂(regenerating). However, it should be noted that first packed bed 12 aand second packed bed 12 b may each alternate between filtration andregeneration operating stages.

Heat generated exothermically by adsorption of carbon dioxide by thefirst sorbent material 16 a may be transferred to the second packed bed12 b. The second packed bed 12 b may receive heat from the first packedbed 12 a to provide energy for CO₂ desorption by second sorbent material16 b. By transferring heat between first packed bed 12 a and secondpacked bed 12 b, heat exchanger assembly 60 may be substantiallyisothermal. Once first sorbent material 16 a of first packed bed 12 a issaturated with CO₂, the operation of first packed bed 12 a and secondpacked bed 12 b is reversed and second packed bed 12 b begins adsorbingCO₂ and water, while first packed bed 12 a begins regenerating.

Referring to FIG. 3, a packed bed for a heat exchanger is shown inaccordance with various embodiments. Packed bed 12 may include one ormore fin layers 30 a, 30 b, 30 c, 30 d separated by one or moreperforated sheets 32 a, 32 b, 32 c. Each of fin layers 30 a, 30 b, 30 c,30 d and perforated sheets 32 a, 32 b, 32 c may be configured to conductheat and may be in thermal communication with the adjacent layers. Eachof fin layers 30 a, 30 b, 30 c, 30 d and perforated sheets 32 a, 32 b,32 c may comprise aluminum, aluminum alloy, steel, or stainless steel,copper or other materials. Each of perforated sheets 32 a, 32 b, 32 cmay define a plurality of apertures or perforations 70. Perforations 70may permit airflow between adjacent fin layers 30 a, 30 b, 30 c, 30 d.

A first perforated sheet 32 a may be disposed between a first fin layer30 a and a second fin layer 30 b. A second perforated sheet 32 b bedisposed between second fin layer 30 b and a third fin layer 30 c. Athird perforated sheet 32 c be disposed between third fin layer 30 c anda fourth fin layer 30 d. The layers are coupled together by a processsuch as brazing, soldering, welding or other suitable process. Thesorbent material 16 discussed with respect to FIG. 1A may at leastpartially fill a volume defined by one or more of fin layers 30 a, 30 b,30 c, 30 d and perforated sheets 32 a, 32 b, 32 c. Thus, packed bed 12may include at least a first fin layer 30 a thermally coupled to asecond fin layer 30 b by a first perforated sheet 32 a therebetween.Sorbent material 16 may be disposed within a volume defined by at leastone of the first fin layer 30 a or the second fin layer 30 b. In variousembodiments, fin layers 30 a, 30 b, 30 c, 30 d may comprise lancedoffset fins, corrugated fins, louvered fins, wavy fins, pin fins,straight fins, or other fin arrangement.

With reference to FIG. 4, a sorbent bed having lanced offset fins isshown in accordance with various embodiments. Fin layers 30 a, 30 b, 30c, 30 d and perforated sheets 32 a, 32 b, 32 c may be configured topermit airflow in multiple directions through packed bed, including inthe x-direction, y-direction, and z-directions in relation to theprovided xyz axis. In various embodiments, the lances for the fin layersand perforations of the perforated sheets facilitate multi-directionalairflow. Fin layers 30 a, 30 b, 30 c, 30 d may be disposed within packedbed 12 having alternating orientations. Each fin within a fin layer mayhave peaks 80 and valleys 82 which may be arranged to allow airflow invarious directions including a first direction D1 and a second directionD2, wherein second direction D2 may be substantially perpendicular tothe first direction D1. For first fin layer 30 a may comprise aplurality of first lanced offset fins oriented with one of its flowpaths in the first direction D1, and the second fin layer 30 b maycomprise a plurality of second lanced offset fins oriented with one ofits flow paths in the first direction D2. Thus, first fin layer 30 a andsecond fin layer 30 b may be staggered with at least one staggeredairflow path. By staggering the lanced offset fins of each adjacent finlayer 30 a, 30 b, 30 c, 30 d, airflow may be encouraged in variousdirections through packed bed 12. The lanced offset fins of fin layer 30a, 30 b, 30 c, 30 d may allow for a compact packed bed 12 and efficientuse of the volume of within packed bed 12.

With reference to FIGS. 5A, 5B and 5C, various configurations of apacked bed for a heat exchanger are shown, in accordance with variousembodiments. A packed bed for a heat exchanger assembly 60 (of FIG. 2)may include various arrangements of fin layers and perforated sheets.The height of packed beds 100, 110, 120 may be configured according tothe heat exchanger design. Fin layers 102, 112, 122 further providestructural support for packed beds 100, 110, 120. FIGS. 5A, 5B and 5Cshow packed beds 100, 110, 120 having different quantities of fin layers102, 112, 122 and show fin layers 102, 112, 122 having differentheights. The height and quantity of fin layers 102, 112, 122 may beselected according to the heat exchanger in which the packed beds 100,110, 120 are used.

With reference to FIG. 6, a method 200 for manufacturing a packed bedfor a heat exchanger, in accordance with various embodiments. The method200 of manufacturing a packed bed for a heat exchanger may comprise thesteps of forming a first fin layer configured to fit within a frame(step 202), forming a second fin layer configured to fit within theframe (step 204), disposing a perforated sheet between the first finlayer and the second fin layer step (206), brazing the first fin layer,perforated sheet, and second fin layer to form a packed bed (step 208),disposing the packed bed within the frame (step 210), applying a sorbentmaterial within the packed bed (step 212), and stacking a plurality ofthe packed beds with adjacent packed beds in thermal communication (step214) to form the heat exchanger.

Step 202 may further comprise cutting a first fin layer. The first finlayer may comprise first lanced offset fins. Step 204 may furthercomprise cutting a second fin layer. The second fin layer may comprisesecond lanced offset fins. Steps 202 and 204 may further compriseforming the first fin layer and the second fin layer by staggering thefirst lanced offset fins with the second lanced offset fins. Step 210may further comprise sealing the packed bed within the frame. The framemay define a fill port. Step 212 may further comprise injecting thesorbent material into the frame through the fill port. The sorbentmaterial may be configured to adsorb carbon dioxide.

Benefits and other advantages have been described herein with regard tospecific embodiments. Furthermore, the connecting lines shown in thevarious figures contained herein are intended to represent exemplaryfunctional relationships and/or physical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical system. However, the benefits, advantages, and any elementsthat may cause any benefit or advantage to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of the disclosure. The scope of the disclosure isaccordingly to be limited by nothing other than the appended claims, inwhich reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore.” Moreover, where a phrase similar to “at least one of A, B, or C”is used in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “various embodiments”, “oneembodiment”, “an embodiment”, “an example embodiment”, etc., indicatethat the embodiment described may include a particular feature,structure, or characteristic, but every embodiment may not necessarilyinclude the particular feature, structure, or characteristic. Moreover,such phrases are not necessarily referring to the same embodiment.Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described. After reading the description, itwill be apparent to one skilled in the relevant art(s) how to implementthe disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A heat exchanger assembly, comprising: a first packed bed having a first fin layer comprising first lanced offset fins, a second fin layer comprising second lanced offset fins, and a first sorbent material disposed within the first packed bed; and a second packed bed in thermal communication with the first packed bed, the second packed bed having a third fin layer and a second sorbent material disposed within the second packed bed, wherein the first lanced offset fins are staggered with the second lanced offset fins to facilitate multi-directional airflow and allow for a compact configuration of the first packed bed.
 2. The heat exchanger assembly of claim 1, wherein the first packed bed comprises a perforated sheet brazed with the first fin layer.
 3. The heat exchanger assembly of claim 1, wherein the first fin layer, the second fin layer and the perforated sheet comprise aluminum.
 4. The heat exchanger assembly of claim 1, wherein the first sorbent material and the second sorbent material are configured to adsorb and desorb carbon dioxide.
 5. The heat exchanger assembly of claim 4, wherein heat generated exothermically by adsorption of carbon dioxide by the first sorbent material is transferred to the second packed bed.
 6. The heat exchanger assembly of claim 5, wherein the second packed bed receives heat from the first packed bed, and wherein the heat exchanger assembly is substantially isothermal. 